The invention provides a method of a vortex light beam generating system with a tunable orbital angular momentum state. The method is different from a single-valued production method and an arbitrary value can be generated through light path circulation. Common Gaussian pulse light enters a circulation light path, the topology loads of outgoing light beams are increased by an order every time the incident light beams pass through an order of a spiral phase plate, and the outgoing light beams are transmitted to a light path control device; when a control signal is set, the light beams are reflected at the optical grating crystal position and enter the circulation light path; multiple times of light path circulation is conducted on the incident vortex light beams, and namely an orbital angular momentum value is increased multiple times until the orbital angular momentum value reaches a needed value l; when the control signal is reset, the light beams are transmitted at the optical grating crystal position, and the generated vortex light beams at the specific state l are output. If the duration for single time of light path circulation is set to be Tc and the duration for generating the light beams is set to be T, the orbital angular momentum value l of the outgoing light beams is T/Tc, and therefore generation of the vortex light beams with the specific orbital angular momentum state is achieved through time control. The vortex light beam generating system has the tunable function and can be freely controlled according to the needed light path circulation duration, the vortex light beams with different states l are generated, and the structure is clear.